diff options
| -rw-r--r-- | Documentation/i2c/fault-codes | 4 | ||||
| -rw-r--r-- | drivers/i2c/i2c-core-base.c | 3 | ||||
| -rw-r--r-- | include/linux/i2c.h | 34 |
3 files changed, 41 insertions, 0 deletions
diff --git a/Documentation/i2c/fault-codes b/Documentation/i2c/fault-codes index 47c25abb7d52..0cee0fc545b4 100644 --- a/Documentation/i2c/fault-codes +++ b/Documentation/i2c/fault-codes @@ -112,6 +112,10 @@ EPROTO case is when the length of an SMBus block data response (from the SMBus slave) is outside the range 1-32 bytes. +ESHUTDOWN + Returned when a transfer was requested using an adapter + which is already suspended. + ETIMEDOUT This is returned by drivers when an operation took too much time, and was aborted before it completed. diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index 28460f6a60cc..926ca0a7477f 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -1232,6 +1232,7 @@ static int i2c_register_adapter(struct i2c_adapter *adap) if (!adap->lock_ops) adap->lock_ops = &i2c_adapter_lock_ops; + adap->locked_flags = 0; rt_mutex_init(&adap->bus_lock); rt_mutex_init(&adap->mux_lock); mutex_init(&adap->userspace_clients_lock); @@ -1865,6 +1866,8 @@ int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) if (WARN_ON(!msgs || num < 1)) return -EINVAL; + if (WARN_ON(test_bit(I2C_ALF_IS_SUSPENDED, &adap->locked_flags))) + return -ESHUTDOWN; if (adap->quirks && i2c_check_for_quirks(adap, msgs, num)) return -EOPNOTSUPP; diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 65b4eaed1d96..cba59d66c00d 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -680,6 +680,8 @@ struct i2c_adapter { int timeout; /* in jiffies */ int retries; struct device dev; /* the adapter device */ + unsigned long locked_flags; /* owned by the I2C core */ +#define I2C_ALF_IS_SUSPENDED 0 int nr; char name[48]; @@ -762,6 +764,38 @@ i2c_unlock_bus(struct i2c_adapter *adapter, unsigned int flags) adapter->lock_ops->unlock_bus(adapter, flags); } +/** + * i2c_mark_adapter_suspended - Report suspended state of the adapter to the core + * @adap: Adapter to mark as suspended + * + * When using this helper to mark an adapter as suspended, the core will reject + * further transfers to this adapter. The usage of this helper is optional but + * recommended for devices having distinct handlers for system suspend and + * runtime suspend. More complex devices are free to implement custom solutions + * to reject transfers when suspended. + */ +static inline void i2c_mark_adapter_suspended(struct i2c_adapter *adap) +{ + i2c_lock_bus(adap, I2C_LOCK_ROOT_ADAPTER); + set_bit(I2C_ALF_IS_SUSPENDED, &adap->locked_flags); + i2c_unlock_bus(adap, I2C_LOCK_ROOT_ADAPTER); +} + +/** + * i2c_mark_adapter_resumed - Report resumed state of the adapter to the core + * @adap: Adapter to mark as resumed + * + * When using this helper to mark an adapter as resumed, the core will allow + * further transfers to this adapter. See also further notes to + * @i2c_mark_adapter_suspended(). + */ +static inline void i2c_mark_adapter_resumed(struct i2c_adapter *adap) +{ + i2c_lock_bus(adap, I2C_LOCK_ROOT_ADAPTER); + clear_bit(I2C_ALF_IS_SUSPENDED, &adap->locked_flags); + i2c_unlock_bus(adap, I2C_LOCK_ROOT_ADAPTER); +} + /*flags for the client struct: */ #define I2C_CLIENT_PEC 0x04 /* Use Packet Error Checking */ #define I2C_CLIENT_TEN 0x10 /* we have a ten bit chip address */ |